MemoryError when generating indexes

Vernier Networks has a relatively small/medium mailing
list archive (only ~238megs) that can not be
regenerated in 512megs of memory. (Once the machine
needs a reboot, this will increase to 1gig.) It dies
with a MemoryError supplied below:
Updating index files for archive [2002-May]
Traceback (most recent call last):
  File "/home/mailman/bin/arch", line 129, in ?
    main()
  File "/home/mailman/bin/arch", line 119, in main
    archiver.close()
  File "/home/mailman/Mailman/Archiver/pipermail.py",
line 304, in close
    self.update_dirty_archives()
  File "/home/mailman/Mailman/Archiver/HyperArch.py",
line 934, in update_dirty_archives
    self.__super_update_dirty_archives()
  File "/home/mailman/Mailman/Archiver/pipermail.py",
line 513, in update_dirty_archives
    self.update_archive(i)
  File "/home/mailman/Mailman/Archiver/HyperArch.py",
line 937, in update_archive
    self.__super_update_archive(archive)
  File "/home/mailman/Mailman/Archiver/pipermail.py",
line 417, in update_archive
    self.__set_parameters(archive)
  File "/home/mailman/Mailman/Archiver/pipermail.py",
line 332, in __set_parameters
    firstdate = self.database.firstdate(archive)
  File
"/home/mailman/Mailman/Archiver/HyperDatabase.py", line
207, in firstdate
    self.__openIndices(archive)
  File
"/home/mailman/Mailman/Archiver/HyperDatabase.py", line
238, in __openIndices
    self.__closeIndices()
  File
"/home/mailman/Mailman/Archiver/HyperDatabase.py", line
259, in __closeIndices
    index.close()
  File
"/home/mailman/Mailman/Archiver/HyperDatabase.py", line
186, in close
    fp.write(marshal.dumps(self.dict))
MemoryError

and I also have an IOError on a lock file.

I will be looking at it, but since I do not know
Pipermail, I won't progress very far.

[http://sourceforge.net/tracker/index.php?func=detail&aid=647102&group_id=103&atid=100103]